Microelectromechanical systems (MEMS) may provide highly sensitive and useful devices, such as microphones and loudspeakers, on the micro-scale. A MEMS microphone may have at least one electrode and a diaphragm and function as a transducer.
In general, a semiconductor chip (which may also be referred to as a die, chip, or microchip) may be processed by semiconductor technologies on and/or in a wafer (or a substrate or a carrier). The semiconductor chip may include one or more MEMS, which are formed during semiconductor technology processing.
During processing, the semiconductor chip may be mechanically stressed. For example, mechanical stress may occur during singulation of the semiconductor chip from the wafer, during handling of the semiconductor chip by positioning systems (e.g., Pick and Place applications), during thermal treatment of the semiconductor chip, e.g., during encapsulation or soldering of the semiconductor chip. Alternatively or additionally, the semiconductor chip may be mechanically stressed during operation of the readily processed chip. For example, mechanical stress may occur due to thermal fluctuations during operation of the chip.
Such mechanical stresses (also referred to as mechanical loads) may be transferred to the MEMS on or in the semiconductor chip, which may lead to a deformation (also referred to as strain) of the microelectromechanical system. The impact of mechanical stress on the MEMS (or a device operating the MEMS) may result in an uncontrolled or undefined behavior of the MEMS, e.g., malfunction or inaccurate function (e.g., inaccurate measurement results), and/or may damage the MEMS. For example, a MEMS and/or a device operating the MEMS (especially silicon microphones) would be sensitive to stress due to assembly or thermal fluctuations. In other words, due to factors related to assembly and the bulk of the substrate of the MEMS device, stress coupled into the MEMS structure may cause changes in the structure and sensitivity of the device. After assembly, the deformation of the MEMS may remain, which complicates the fabrication of accurate working devices. MEMS with a high sensitivity are especially affected by the stress arising from assembly.